Iothread

[TwiX]

Hi,

I just built a new KVM virtual machine, I first decided to put only one vdisk with few partitions (on a RAID10 ZFS pool with fast SSD), one partition for OS and the other for datas (SQL Server databases).

I'm wondering if instead of using only one vdisk it could be better to use 2 vdisks and put SQL Server databases on 2nd vdisk.

iothread couldn't be used with backups, so I don't want it.

Anyway, when OS is completely loaded, in my case,I don't see any reason for OS vdisk to reclaim high IOPS (if OS is not swapping of course), so IMHO iothread is only required when 2 or more vdisks need high IOPS? Do you agree ?

Thanks in advanced !

Antoine

 

[dcsapak]

when you do not use iothreads, all io is done by one thread in qemu, only if you use iothreads, each disk gets its own thread

 

[TwiX]

Thanks for your answer.

My question would be : is there a need to settle iothread while only one disk require IOPS ?

Antoine

 

[dcsapak]

you do not need to set iothread at all, but it can improve disk performance. i would suggest that you take the time and test/benchmark
it with/without and see which features/performance you need